Warren has generated considerable speculation about a possible run for the White House in 2020, recently saying she would take a "hard look" at a presidential bid after the Senate race was over.

The former Harvard Law School professor recently released a DNA test suggesting that a distant ancestor was Native American, an effort to rebut Trump's frequent mockery of her claim to Native American heritage.

Warren downplayed her clashes with Trump after voting Tuesday morning near her home in Cambridge.

"For me this is about the people of the Commonwealth of Massachusetts," Warren told reporters. "It's about whether or not we're able to protect health care, whether or not our students get a break or get crushed by student loan debt."

Diehl, speaking earlier in the day outside a polling place in his hometown of Whitman, said he was still hoping for a win. "We actually think this is going to be one of those days that surprises everybody," he said.

The contest between the two was testy at times, with each candidate looking to score points with voters by chipping away at the other.

Warren said Diehl would be a rubber stamp in Washington for Trump's agenda even when it's not in the interest of most Massachusetts residents.

"My opponent has said he's with Donald Trump 100 percent of the time," Warren said.

Diehl argued Warren has spent too much time traveling around the country to stump — and raise money — for fellow Democrats running for Congress. He said she should quit and run full time for the White House.

"Sen. Warren, she's very focused on herself, focused on a run for the White House and does not seem to have that same commitment for the state," he said during the campaign, arguing he could offer Massachusetts a seat at the table in the GOP-controlled Senate and Republican White House.

For fans of Warren, the campaign played out in part as a test run for a possible 2020 clash between Warren and Trump.

Trump taunts of "Pocahontas" directed at Warren in part prompted her decision to release the DNA test. Warren has said the decision to release the test results was also part of a wider effort on her part to be an open book.

"I put it all out there. Ten years of tax returns. All my employment records, And yeah, I even took a DNA test. It's there. It's on the internet. Anybody can take a look at it," she told The Associated Press in a recent interview.

Warren had said her decision to campaign for Democrats in other states was part of a wider goal to help flip the Senate to make it easier for Democrats to push a more ambitious agenda in line with what she said are the goals of most Massachusetts voters.

Even though she was running against Diehl, the figure of Trump, who remains unpopular in Massachusetts where he garnered less than 34 percent of the 2016 vote, hung over the contest.

Asked about the worst thing Trump has done during his two years in office, Warren pointed to what she described as his embrace of authoritarian figures like Russian President Vladimir Putin or North Korea's Kim Jong Un.

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For AP's complete coverage of the U.S. midterm elections: http://apne.ws/APPolitics